The objective of this paper focused on the ffects of dietary nucleotides (NT) on histopathological alternations of striped catfish Pangasianodon hypophthalmus, after exposure to water-borne silver nanoparticles (AgNPs) and silver nitrate (AgNO3). Fish were fed with a diet containing nucleotide (0.75%) or control diet for 10 weeks and then divided into 3 experiments including control, 20 µg L-1 of AgNPs or AgNO3 for 10 days. At the end, histopathological changes in gill, liver and kidney were evaluated using haematoxylin-eosin technique. Water-borne AgNPs or AgNO3 caused some distinctive histopathological alterations in both feeding group. The most important damages were observed in epithelial cell hyperplasia, inflammation and necrotic epithelial cell in the gills, pigmentation, fiber cells and cytoplasmic vacuolization of hepatocytes in the liver and visualization of red blood cells and eosinophils, glomerular and tubular necrosis in the kidney. Based on organ index (Iorg), the highest damages were observed in the tissues of the fish fed on the control diet and exposed to 20 µg L-1 of AgNPs. No significant differences were observed in histopathological alterations between two feeding groups when compare the same organs with similar pollutant (kind and concentration). It could be concluded that dietary NT could not improve the fish ability against water-borne AgNPs or AgNO3.